Recession cone


In mathematics, especially convex analysis, the recession cone of a set is a cone containing all vectors such that recedes in that direction. That is, the set extends outward in all the directions given by the recession cone.

Mathematical definition

Given a nonempty set for some vector space, then the recession cone is given by
If is additionally a convex set then the recession cone can equivalently be defined by
If is a nonempty closed convex set then the recession cone can equivalently be defined as

Properties

The asymptotic cone for is defined by
By the definition it can easily be shown that
In a finite-dimensional space, then it can be shown that if is nonempty, closed and convex. In infinite-dimensional spaces, then the relation between asymptotic cones and recession cones is more complicated, with properties for their equivalence summarized in.

Sum of closed sets